The invention relates to a dispensing head for a product of a liquid to viscous consistency, comprising a rigid cap and an elastic closing element provided with at least one closed dispensing slit, capable of opening under the thrust of the product and of returning to its initial position when this thrust ceases to be applied. The invention also relates to a dispensing unit for the product fitted with this dispensing head, as well as to a method for manufacturing the dispensing head.
The aim of the invention is in particular to provide a dispensing unit of the kind having a semi-rigid or flexible reservoir fitted with a rigid, or semi-rigid dispensing head provided with an elastically deformable dispensing opening.
The dispensing unit of the invention is intended more particularly to equip a compressible reservoir containing the product, and to permit its dispensing in good, clean conditions. This product may, in particular, be a cosmetic, dermatological or food product, such, for example, as shampoo, a hair gel, a shower foam gel, liquid soap, a face cream, a body lotion, liquid make-up or a household product or an adhesive.
From GB-A-1 476 620 there is known a tube, for a liquid product, which is fitted with a dispensing head. This dispensing head has a rigid cap provided with an outlet opening for the product in the form of an attached elastic membrane into which a slit is cut by mechanical cutting. A fixing ring holds the membrane in position on the dispensing head. When the user exerts pressure on the tube, the edges of the slit diverge under the thrust of the product and close again when the pressure of the product stops. The edges of the slit are contiguous, which renders superfluous the closing of the outlet opening by a stopper.
However, this tube has drawbacks from the point of view of its manufacture. Indeed, the assembly of the head consisting of two or three separate pieces (a cap, membrane, fixing ring for the membrane) requires recourse to a special assembly machine, which increases the manufacturing cost. Moreover, obtaining the slit is effected in particular by cutting, requiring the take-up of the membrane in another machine, which considerably increases still further the cost price of the dispensing head of the prior art.
Moreover, there is known, from EP-A-0 545 678 and U.S. Pat. No. 5,339,995, a dispensing head comprising a slit circular membrane provided with a peripheral fixing sleeve folded into a U-shape. As in the embodiment according to GB-A-1 476 620 mentioned above, the edges of the slit are obtained by the mechanical cutting of the slit. Therefore, this dispensing head is onerous and disadvantageous from an economic point of view. For this reason it is not suitable, in particular for a widely distributed product, such as a shampoo or a dishwashing product, for which the price must be moderate.
Moreover, EP-A-O 111 798 describes a dispensing head comprising a rigid cap and an elastic closing and dispensing element joined to the cap. According to this prior art, the elastic closing element has a slit formed by two parallel lips disposed in particular to project on the outer side of the elastic element, so that a recess is formed on the inner side of the element, in a zone in the proximity of the edges of the lips.